U.S. Pat. No. 3,839,318, Mansfield, issued Oct. 1, 1974, discloses a process for preparing alkyl glycosides by direct, acid catalyzed reaction of a higher alcohol and a saccharide. The disclosed catalysts are mineral acids such as hydrochloric and sulfuric acid and an acid cation exchange resin. Neutralization of the catalyst at the end of the reaction is with sodium hydroxide.
U.S. Pat. No. 3,547,828, issued Dec. 17, 1970, discloses a process for preparing higher alkyl glycosides by first reacting a saccharide with a lower alcohol (e.g., butanol) in the presence of an acid catalyst to form the lower alkyl glycoside, which is then reacted with the higher alcohol to effect transacetylation thereby forming the higher alkyl glycoside. The acid catalysts disclosed are mineral acids (e.g., H.sub.2 SO.sub.4, HNO.sub.3) and organic acids such as p-toluene sulfonic acid and methane sulfonic acid. It is stated that in general any "Lewis acid" may be used. Sulfuric acid is indicated as preferred. Neutralization of the catalyst at the end of the reaction is with sodium hydroxide.
U.S. Pat. No. 3,598,865, Lew, issued Aug. 10, 1971, discloses preparation of higher alkyl glycosides by acid catalyzed reaction of a saccharide and a higher alcohol in the presence of a lower alcohol (designated as a "latent solvent"). The acids disclosed as suitable catalysts are sulfuric, hydrochloric, phosphoric and p-toluenesulfonic acids and boron trifluoride. Neutralization of the catalyst at the end of the reaction is with sodium hydroxide.
U.S. Pat. No. 3,219,656, Boettner, issued Nov. 23, 1965, discloses a process for preparing higher alkyl glycosides by reaction of a higher alcohol with a saccharide in the presence of a lower alcohol and a macroreticular sulfonic acid ion exchange resin. Neutralization of the finished reaction mix is with calcium hydroxide.
It is desirable that alkyl glycosides, particularly those intended for use as, for example, surfactants in consumer products, be essentially colorless, or at least have very low color content.
It is the object of the present invention to provide improved color in alkyl glycosides.